The present invention relates to an outlet device for a jet engine and also a jet-propelled craft comprising a jet engine with such an outlet device.
The term jet engine is intended to include various types of engine which take in air at relatively low speed, heat it via combustion and eject it at much higher speed. The term jet engine includes turbojet engines and turbofan engines, for example.
The jet engine conventionally comprises a compressor section for compression of the incoming air, a combustion chamber for combustion of the compressed air and a turbine section arranged after the combustion chamber, which turbine section is rotationally connected to the compressor section in order to drive the latter with the aid of the energy-rich gas from the combustion chamber. The compressor section usually comprises a low-pressure compressor and a high-pressure compressor. The turbine section usually comprises a low-pressure turbine and a high-pressure turbine. The high-pressure compressor is connected in a rotationally fixed manner to the high-pressure turbine via a first shaft, and the low-pressure compressor is connected in a rotationally fixed manner to the low-pressure turbine via a second shaft.
The jet engine can be used for propulsion of various types of jet-propelled craft including both landcraft and watercraft, but the invention is primarily intended to be applied in an aircraft, and then in particular in an aircraft engine. It is previously known to protect an aircraft against possible attack by providing the aircraft with a low signature. In this context, signature means contrast against the background. For example, hot structures and hot exhaust gases give rise to an IR signature.
It is also known that a tail fin on the craft gives rise to a strong radar signature. It would therefore be desirable to bring about steering of a craft in a different way.
It is desirable to produce an outlet device for a jet engine which will provide the craft propelled by the jet engine with alternative steering. Also aimed at is an outlet device for a jet engine which affords opportunities for providing the jet engine and/or the craft propelled by the jet engine with a signature reduction.
According to an aspect of the present invention, an outlet device comprises a number of fixed ducts, each with a gas intake and a gas outlet for conducting a gas from the jet engine. At least two of the outlets of said gas ducts open in different directions. Furthermore, a gas distribution arrangement is arranged at said gas intakes for selective distribution of the gas to said ducts.
By controlling the gas distribution arrangement in a suitable way, it is possible to vector the thrust from the engine and thus to increase the maneuverability of the craft, and the possibilities for flying the craft stably are thus improved.